Systems and methods for providing quality of service to RFID

ABSTRACT

Embodiments of the present invention include systems and methods for providing Quality of service to RFID. In one embodiment the present invention includes a method of providing quality of service in an RFID network comprising storing RFID priority information corresponding to the RFID network, wherein the RFID network comprises one or more tags and one or more readers mapping the RFID priority information into priority information corresponding to a second network.

CLAIM OF BENEFIT TO PRIOR APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 11/809,013, filed May 30, 2007, published as U.S.Publication 2008/0297312, and now issued as U.S. Pat. No. 7,978,050. Thecontents of U.S. Publication 2008/0297312, now issued as U.S. Pat. No.7,978,050, are hereby incorporated by reference.

BACKGROUND

The present invention relates to radio frequency identification(“RFID”), and in particular, to systems and methods for providingquality of service (“QoS”) to RFID.

Radio Frequency Identification (RFID) is a wireless technology that useselectronic tags for storing data. RFID tags are read when they are closeto a transmitted radio signal from an RFID reader. RFID readers manageRFID tags and pass their information onto network servers, corporatedatabases and business applications. The readers typically act like agateway between the tags and the corporate servers/databases byproviding an RF interface to the tags on one side and another networkinterface on the other side.

As the price of tags drops, RFID tags will become prevalent in thefuture and as such will provide large volumes of network traffic throughthe readers. RED applications include short range and long rangecommunication and cover areas such as supply chain automation, assettracking, medical smartcard applications, people tracking, manufacturingparts tracking, supermarket active shelves and trolley tracking,warehouse inventory management, security and access control, andlivestock tracking. Telemetry applications include gathering data fortemperature, motion, sound, video, light and moisture. RFID data fromthese different industries and have different requirements in terms ofguaranteed delays and required bandwidth. Since network bandwidth islimited and congestions can occur it is important to differentiatebetween different types of RFID network traffic. A best effort type ofRFID network is not acceptable for mission critical RFID data because itdoes not provide for guaranteed bandwidth or priority-based treatment ofRFID data. It is therefore necessary to provide QoS for RFID data wherethe accuracy and urgency of the RFID data is important.

The present invention provides systems and methods for providing qualityof service (“QoS”) to RFID to improve RFID network performance.

SUMMARY

Embodiments of the present invention include systems and methods forproviding Quality of Service to RFID. In one embodiment the presentinvention includes a method of providing quality of service in an RFIDnetwork comprising storing RFID priority information corresponding tosaid RFID network, wherein the RFID network comprises one or more tagsand one or more readers, and mapping the RFID priority information intopriority information corresponding to a second network.

In one embodiment, the RFID priority information is stored on one ormore tags.

In one embodiment, the RFID priority information corresponding to one ormore tags is stored on a reader.

In one embodiment, the RFID priority information comprises tag priorityinformation and reader priority information.

In one embodiment, the RFID priority information corresponding to one ormore tags is stored external to the tag.

In one embodiment, the RFID priority information corresponding to one ormore tags is cached on an access point in the second network.

In one embodiment, the RFID priority information is stored on one ormore readers.

In one embodiment, the RFID priority information is based on attributesof the RFID network.

In one embodiment, the attributes of the RFID network include thelocation of a reader, a time, or an application type.

In one embodiment, the second network is a wired local area network, awireless local area network, or a cellular network.

In one embodiment, the mapping is specified by a mapping algorithm.

In one embodiment, the priority information for the second network iscalculated based on the RFID priority information of the RFID network,the number of priority levels available on the RFID network, and thenumber of available priority levels on the second network.

In one embodiment, a reader modifies the RFID priority informationstored on a tag.

In one embodiment, the reader updates RFID priority information storedon the reader corresponding to the tag.

In one embodiment, the reader transmits the modified RFID priorityinformation on the tag to one or more other readers.

In another embodiment, the present invention includes a method ofproviding quality of service in an RFID network comprising receiving anRFID event on an RFID reader, associating first priority informationwith the RFID event, and executing the RFID event on said RFID readerbased on the first priority information.

In one embodiment, the method further comprises associating secondpriority information with the RFID event on a network external to saidRFID network, sending the RFID event and second priority information tosaid RFID reader, and executing the RFID event based on the first andsecond priority information.

In one embodiment, the first priority information is stored on thereader.

In one embodiment, the first priority information is stored external tothe reader.

In one embodiment, the first priority information comprises tag priorityinformation.

In one embodiment, the first priority information comprises readerpriority information.

In one embodiment, the first priority information comprises tag andreader priority information.

In another embodiment, the present invention includes a system includingan RFID network comprising one or more RFID readers coupled to at leastone second network over a communication channel, a plurality of RFIDtags coupled to at least one of the RFID readers, and RFID priorityinformation, wherein the RFID reader prioritizes processing RFIDinformation based on the RFID priority information.

In one embodiment, the RFID information comprises RFID events receivedfrom the second network, and wherein the RFID reader receives an RFIDevent, associates RFID priority information with the RFID event, andexecutes the RFID event on said RFID reader based on the RFID priorityinformation.

In one embodiment, the reader maps the RFID priority information intopriority information corresponding to the second network.

In one embodiment, the RFID priority information is stored on thereader.

In one embodiment, the RFID priority information comprises tag priorityinformation.

In one embodiment, the RFID priority information comprises readerpriority information.

In one embodiment, one or more of the RFID readers are multimode readerswith multiple radios, and wherein at least one RFID reader transmits andreceives information using a first communication channel based on firstRFID priority information, and wherein the at least one RFID readertransmits and receives information using a second communication channelbased on second RFID priority information having a higher priority thanthe first RFID priority information.

In one embodiment, the first communication channel is a communicationchannel between the at least one RFID reader and another RFID reader,and the second communication channel is a communication channel betweenthe at least one RFID reader and the second network.

These and other features of the present invention are detailed in thefollowing drawings and related description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a RFID system according to one embodiment of thepresent invention.

FIG. 2A illustrates a method of providing QoS for downstream data in aRFID system according to one embodiment of the present invention.

FIG. 2B illustrates a method of providing QoS for upstream data in aRFID system according to one embodiment of the present invention.

FIG. 2C illustrates a method of providing QoS in a RFID system accordingto one embodiment of the present invention.

FIG. 3 illustrates a RFID system according to one embodiment of thepresent invention.

FIG. 4 illustrates a RFID system according to one embodiment of thepresent invention.

FIG. 5 illustrates a RFID system according to one embodiment of thepresent invention.

FIG. 6 illustrates differential services (DS).

DETAILED DESCRIPTION

Described herein are techniques for providing quality of service (“QoS”)to RFID to improve RFID network performance. In the followingdescription, for purposes of explanation, numerous examples and specificdetails are set forth in order to provide a thorough understanding ofthe present invention. It will be evident, however, to one skilled inthe art that the present invention as defined by the claims may includesome or all of the features in these examples alone or in combinationwith other features described below, and may further includemodifications and equivalents of the features and concepts describedherein.

FIG. 1 illustrates a RFID system according to one embodiment of thepresent invention. RFID system 100 includes RFID network 170, which iscoupled to another network 160. Network 160 may send commands to RFIDnetwork 170 through network channel 180. These commands may include RFIDevents, which are used to retrieve data from RFID tags. By altering theorder and time these RFID events are executed, the RFID network mayprovide QoS to the RFID system. QoS refers to a defined level ofperformance in a data communications system. In the absence of QoS,networks typically operate on a best effort scheme where all packetshave equal priority regardless of content and there are no guaranteesregarding reliability, delay, and throughput. Thus, if the networkexperiences congestion, all packets are equally likely to be dropped.QoS, on the other hand, provides priority-based treatment of certaintraffic. This decreases the likelihood of loss in high priority packets.Depending on the type of data being retrieved, QoS requirements maydiffer. For example, video and voice services can typically toleratesome error rates but require low delivery delays, while businesscritical traffic is not time-critical but is loss-sensitive. To ensurethat real-time voice and video are delivered without undue delay, aguarantee of bandwidth may be required. This may be accomplished bygiving network priority to real-time data over non real-time data. Byproviding higher priority/network bandwidth to high priority RFID eventsover lower priority RFID events as well as non-priority network traffic(e.g., TCP-based events), QoS for RFID data may be beneficial tocritical RFID applications and information. Another advantage of QoS inRFID networks is higher prioritization of time consuming operationswithin the RFID network or second network so that time-sensitive datafrom tags may get to their destinations as quickly as possible.

RFID network 170 comprises RFID tag 110 and RFID reader 140. As commandscomprising RFID events are received by the RFID network, a prioritylevel may be attached to each event. Depending on the priority level,the RFID events may be performed in an order different than the orderthey are received. Therefore, higher priority RFID events may becompleted faster than other RFID events. The priority level of an RFIDevent may be dependent on RFID priority information corresponding to theRFID network. To remain scalable in anticipation of large volumes ofRFID data in the future, the priority level may take into considerationa variety of RFID priority information stored in a variety of locations.For example, factors of the RFID event such as the location andimportance of the RFID tags and readers may affect the priority level.

The RFID priority information may be stored in a variety of locations.In one embodiment, RFID priority information is externally cached. Forexample, RFID priority information may be stored within another network160 coupled to the RFID network 170. In one embodiment, RFID priorityinformation of the RFID network is stored within RFID network 170. Inone example embodiment, the RFID priority information is stored withinthe RFID tag. The RFID tag may also be encoded and the encoding schememay include a header field followed by one or more value fields. At 121,the header may store the ID of the RFID tag. The header may also defineattributes such as the overall length and format of the value fields,while the value fields may contain RFID data. In one example, the headerfield is modified to include RFID priority information corresponding tothe RFID tag (“tag priority information”). This is illustrated in FIG. 1by RFID tag 110 where header field 120 of RFID tag 110 has been modifiedto include priority field 122. This priority field may be used to storethe tag priority information of RFID tag 110. In one embodiment, thistag priority information is a priority value stored in the tag as tagpriority bits. In one example embodiment, the priority bits are writtenonto the tag's header before deployment by readers. In another exampleembodiment, the priority bits are written on the tag's header afterdeployment by readers. For example, a priority value of five may begiven to security tags while a priority value of two may be given toretail inventory tags. In one embodiment, the priority bits are encodedfor a more efficient representation of the priority. For example, thepriority level of a RFID tag capable of eight different priority levelsmay be represented with three priority bits rather than eight. Inanother embodiment, the priority bits are left un-encoded for fasterreading by the reader.

In one embodiment, RFID priority information is stored within the RFIDreader. RFID priority information stored within the RFID reader mayinclude tag priority information and priority information correspondingto the RFID reader (“reader priority information”), or both. Forexample, RFID reader 140 of FIG. 1 includes reader priority informationat 141 and tag priority information 142, which may reside in a table,for example. Tag priority information 142 may store the tag priorityinformation of all tags accessible to the reader. Both types of priorityinformation may be considered prior to attaching a final priority levelto the RFID event. Reader priority information may include theimportance of the data accessed by the reader, the location of thereader, and the applications supported by the reader. For example, thecommands and tag reads of important locations from a RFID securityapplication reader may be given higher priority over low priority tagreads and low priority traffic. This reduces the chance that highpriority packets experience significant delays or drops in congestednetworks.

Readers may be mobile or they may be fixed in location. For example, thereaders could be integrated into existing products such as cellularphones, PDAs, laptops, wireless game consoles, etc. RFID reader 140communicates with network 160 through network channel 180. Networkchannel 180 may be a wired local area network, a wireless local areanetwork (i.e., Bluetooth, Ultra-WideBand (UWB), WiMax, Zigbee, and otherad-hoc/mesh network technologies), or a cellular network (i.e., GPRS,CDMA, GSM, CDPD, 2.5 G, and 3 G). The network support between the readerand the network may include standard protocols (i.e., TCP/IP, UDP, http,SNMP). Since data is being passed from one network to another, prioritylevels available in the RFID network may be different than the prioritylevels available in the secondary network due to differences within theQoS techniques used. Therefore, mapping between the two sets of prioritylevels may be required to ensure that high priority data may travelthrough network 160 with the same or similar urgency as it did in RFIDnetwork 170. In one embodiment, the RFID reader maps priorityinformation corresponding to the RFID network into priority informationcorresponding to network 160. Once the data has been mapped, the readermay pass on the data to network 160 and move on to processing the nextRFID event.

QoS mechanisms such as those specified in the Wireless LAN 802.11estandard, cellular 3GPP Class of Service (CoS) methods, and wired QoSwith IP precedence and Class of Service (CoS) are discussed in theAppendix. RFID networks according to various embodiments of the presentinvention may include mapping priorities between the RFID network andany one of these QoS mechanisms. Briefly, the WLAN 802.11e standarddefines eight levels of priority: two for voice, three for video, twofor background, and one for best effort. The 3GPP standard defines fourclasses for QoS: conversational, streaming, interactive, and background.Wired QoS with IP precedence and CoS define eight levels of service:best effort, four assured forwarding levels, expedited forwarding,Internet and network.

FIG. 2A illustrates a method of providing QoS for downstream data in aRFID system according to one embodiment of the present invention. At251, a RFID event is generated on a second network for retrievinginformation from a RFID network. In one example, this information isdata from a RFID tag. Many RFID events may be grouped as a command sentto the RFID network. At 252, a network priority is associated to theRFID event. The network priority may illustrate the importance of theinformation to the second network. This may allow the second network toprioritize the execution of the RFID events by specifying a QoS level,for example. In one embodiment, the priority is a numerical value. Forexample, assume RFID events 1, 2, and 3 were assigned a first priorityof 2, 4, and 3, respectively. If higher values represent higherpriority, the second network may wish RFID event 2 to be executed first,followed by RFID event 3 and RFID event 1. At 253, the RFID event issent to the RFID reader. The event may be transmitted on a transmissionchannel such as a wired local area network, a wireless local areanetwork, or a cellular network. At 254, the event is received on thereader. Once received, the reader may perform a query to determine if aRFID priority corresponding to the RFID event exists external to thetag, at 255. In one example, this priority is located within a tablestored on the reader. RFID priority information may include tag priorityinformation (e.g., for one or more tags to be read) or reader priorityinformation (e.g., based on a reader's location). In another example,this priority is located on the second network. If a RFID priority doesexist, the reader may request the RFID priority at 256. The request maybe transmitted on a transmission channel such as a wired local areanetwork, a wireless local area network, or a cellular network.Similarly, the RFID priority may be received on the reader by a similartransmission channel at 257. The reader may then associate the RFIDpriority with the RFID event at 258. Association may include combiningthe network priority with the RFID priority to calculate the priority ofthe event. The event may be prioritized against other events on thereader according to the calculated priority at 259. In one embodiment,the prioritization places the event in a queue based on the calculatedpriority. At 260, the event has reached the top of the queue andtherefore, may be executed by transmitting a signal to the RFID tagrequesting data.

FIG. 2B illustrates a method of providing QoS for upstream data in aRFID system according to one embodiment of the present invention. At271, data may be received on the reader from the RFID tag. This data mayinclude RFID tag attributes such as tag ID and priority information. At272, the reader may determine if an externally stored priority exists.Storing the priority of previously read tags may improve the QoS of theRFID system. This information may provide the reader priorityinformation of the tag without accessing the tag itself. In one example,the externally stored priority is the RFID priority in FIG. 2A. If thestored priority does not exist, then the reader may store the priorityat 277. In one example, the reader may store the priority of the tagalong with the tag ID in a table within the reader. In another example,the reader may transmit the priority of the tag along with the tag IDthrough a transmission channel to a remote location such as an accesspoint or a secondary network. The system may also broadcast the priorityof the tag, thereby allowing others to update their stored copy of thepriority of the tag. For example, other readers may synchronize a changein the tag's priority with their copy of the tag's priority. If thestored priority does exist, the reader may access the stored priority at273. At 274, the reader may determine if the priority of the tag isdifferent than the priority stored external to the tag. A discrepancybetween the priority stored externally and the priority stored on thetag may indicate a correction is required. At 275, the reader maydetermine if the externally stored priority should be updated. In oneexample, the externally stored priority is out of synchronization withthe priority on the tag because another reader has changed the tag'spriority without updating the externally stored priority. If an updateis required for the stored priority, the reader may store the prioritytaken from the RFID tag. The reader may also broadcast the priority toother readers at 277. At 276, the reader may determine if the priorityon the tag should be updated. In one embodiment, the reader mayconclude, based on surrounding circumstances, that the priority storedon the tag is incorrect. For example, the tag with a high priority mayhave moved to a less important location. In another example, a tag withlow priority may be attached to an expensive jewelry item, thereforerequiring a higher tag priority. If an update is required on the tagpriority, a rewrite may be triggered at 278. In one embodiment, therewrite may propagate the externally stored priority to the tag'spriority. In one example, the reader transmits the externally storedpriority to the RFID tag through a transmission channel such as a wiredlocal area network, a wireless local area network, or a cellularnetwork. Once the priority of the tag has synchronized with the rest ofthe system, the reader may access its own priority at 279. At 280, thepriority of the reader and the priority of the tag may form a finalcalculated priority. Functions such as maximum, minimum, average,median, sum, tag-determines and reader-determines are examples offunctions that could be used to combine tag and reader priorities. At281, the final calculated priority from 280 may be mapped to a priorityon the second network. Since the set of possible priorities may varydepending on the network, mapping may allow networks to communicatepriority information with one another. At 282, the reader may transmitthe RFID tag data along with the mapped priority to the second networkthrough a transmission channel. With the mapped priority, the secondnetwork may continue to forward the tag data to its destination with anurgency based on the priority of the data.

FIG. 2C illustrates a method of providing QoS in a RFID system accordingto one embodiment of the present invention. At 201, a RFD reader mayreceive a read command from a second network. Commands to the readerscan originate from an access point/base-station, router, or servercontroller, for example. A read command may include many RFID events toretrieve information from many RFID tags accessible to the RFID reader.These RFID events may contain a priority value for implementing QoSduring the transmission of the command from the network to the reader.Introducing QoS during the transmission of the command may reduce theoccurrence of significant delays or drops of high priority data incongested networks by allowing high priority commands and RFID eventspriority over lower priority commands. These priority values may bebased on the QoS method implemented in the second network. The networknode within the second network that initiates the command to the RFIDreader may set the command's priority to the appropriate priority level.This priority level set by the second network may be in a format that isunderstood by the RFID reader. In one embodiment, the second networkthat initiates the command to the RFID reader sets the priority to aformat understandable by the reader. In another embodiment, the readerreceives the priority value in the format used in the second network andmaps the priority to a format understandable by the reader. If a routeror a server controller initiates the command instead of the accesspoint, then such devices may set the priority level.

At 202, the reader may determine if the tags' priority information isstored external to the tag (e.g., in a cache). For example, as describedabove, the tag priority information may be stored within the RFIDreader. In one embodiment, tag priority information is stored in cachememory for faster access. This information may be used in determiningthe order the reader interrogates the tags associated with each RFIDevent. If the tag priority information is stored external to the tag,the reader may retrieve the stored tag priority information. This tagpriority information retrieval may occur at 204. At 205, the reader mayorder the RFID events according to the stored tag priority information.In one embodiment, the reader may order the RFID events into a list. Inone embodiment, this organization of RFID events also takes intoconsideration the reader priority information. In one example, supposethe reader receives a command to interrogate tags 1, 2, and 3. This maybe represented as RFID events 1, 2, and 3. If the command does notimpose a preference for an order, the reader can determine the order.This order may be determined by the stored tag priority informationavailable to the RFID reader. When a reader interrogates a tag for thefirst time, it may store the tag's ID and its priority information. Thepriority information may be stored in various data structures such aslists, queues, and tables. In one example, the second network may alsooptionally store the ID and priority information of the tags (i.e., inan access point). The next time the reader interrogates that tag, it maycheck the priority of that tag and compare it to the priority of othertags waiting for interrogation to determine the order they will beinterrogated. For example, suppose that tags 1, 2, and 3 have previouslybeen read by this reader and have priority levels of 2, 5, and 1,respectively, stored in the reader. The reader may interrogate the tagsin the following order: tag 2, tag 1, and tag 3 where 5 is a higherpriority than 1 and send the data it reads to the network in that order.Thus, the higher priority tags get processed before the lower prioritytags. This may translate to improved QoS in the RFID system.

If the tag priority information is not stored external to the tag (i.e.,cached in the reader), the reader may order the RFID events according tothe priority value assigned to the RFID events by the second network.This reorganization may occur at 203. In one example, the organizationof RFID events also takes into consideration the reader priorityinformation. In the case where the reader receives a command tointerrogate a number of tags that it has not interrogated before and theRFID events do not contain a priority value, the reader may interrogatethe RFID tags in random order. Once the tag information has beenreceived by the reader, the tags' priority information may be cached bythe reader for future QoS-based interrogations. If the command receivedfrom the second network contains tags with and without priorityinformation stored external to the tag, a combination of the methodsdescribed above may be used in ordering the RFID events.

At 206, the reader may interrogate the RFID tag according to the RFIDevent with the highest priority. Interrogation may include sendingsignals to the RFID tag and receiving data from the RFID tag at 214. Asdescribed above, this data may include tag priority information, tag ID,and tag attributes. After the reader has read a particular tag andexamined the priority level of that tag, the reader checks the tag'sstored priority level at 207. Here, the reader may compare the prioritylevel stored on the tag with the tag's stored priority level. In oneexample, the tag's stored priority level is stored in the reader's cachememory. If the tag's priority level has not been stored (e.g., if thistag has not been read before by this reader), the reader may store thepriority level of this tag. In one example, this may include the readercaching the ID and priority of the tag. This enables future QoS-basedinterrogation of that tag by this reader. If the tag's priority levelhas been stored, the reader may check to see if that priority level haschanged. In one embodiment, changes in the actual and stored prioritylevel may lead the reader to update the actual priority level of theRFID tag at 208. For example, differences between the actual and storedpriority values may occur when another reader has edited the prioritylevel of the tag but did not broadcast the change to other readers. Inanother example, the reader may determine (e.g., via programming) thatthe priority level on the tag should be changed and may overwrite thepriority level on the tag to change the priority. This may include thesituation where the RFID tag has moved to a less critical location, forexample. Yet another example is where a reader reads several RFID tagsand as a result of the priority values of all the tag reads, concludesthat one or more priorities need to be changed.

The reader's priority level may be accessed at 209. In RFIDapplications, the reader may provide a priority based on certaincriteria. Such priorities are referred to as priority values or levels.In one example, readers can have pre-assigned location priorities, withthe actual location of the reader being updated via GPS, for example.Other parameters that can affect a reader's priority include time andthe type of application. In one embodiment, the reader's priority levelis stored on the reader itself. This may allow for quick access to thereader's priority information. In another embodiment, the reader'spriority level is stored elsewhere within the RFID network (e.g., in acentral repository). This may remove the necessity of updatingneighboring readers if a reader changes its priority level. At 210, thereader priority level may be combined with the tag priority level toform a final priority, which is an optional step useful in someapplications. In one embodiment, the priority information is combinedthrough RFID application software within the RFID reader. For example,consider the case where the both the reader and the tag include 8different possible priority values. This means there are 64 possibletag-reader priority combinations.

TABLE 1 Examples of tag and reader priority values, and final prioritylevels calculated with three different functions. Final Final Final TagReader Priority Level Priority Level Priority Level Priority Priority(Function: Tag (Function: Reader (Function: Max of Value ValueDetermines) Determines) Tag and Reader) 2 5 2 5 5 4 3 4 3 4

Table 1 shows 2 of the 64 possible combinations to illustrate theoptional process of combining the reader priority level with the tagpriority level. In the first row, the tag and reader levels are 2 and 5,respectively. In the second row, the levels are 4 and 3, respectively.The third column of Table 1 illustrates the case where the finalpriority level calculated by the reader is the tag value (i.e., thereader levels are ignored). The fourth column is the opposite case wherethe reader priority value determines the final calculated priority level(i.e., tag levels are ignored). The latter may also apply to situationswhere there are no tag priority bits and hence, by default, the readerpriorities determine the final priority levels. The last column is anexample where both tag and reader levels are used to arrive at the finalcalculated priority level. In this example, the function used to combinethe levels is P=Max(tag, reader), where the larger of the tag and readerlevels is assigned to the final calculated priority level. In otherexamples, the function used to combine the levels may include minimum,average, median, sum, etc. The RFID application can play a role indetermining how tag and reader priorities are combined. For example, theapplication logic can determine what function is used to combine readerand tag priorities. Some applications may provide more weight to tagpriorities while others may provide more weight to reader priorities. Inone embodiment, the reader may not contain its own priority level,allowing the tag priority level to become the final priority level.

At 211, the RFID reader may map the priority information of a tag topriority information in a second network, herein referred to as anetwork traffic class. The reader may access the descriptions of thenetwork traffic classes and forward data to the rest of the secondnetwork (wireless or wired). Information about the second network'savailable priorities may provide the reader with the informationnecessary to perform the mapping function. In an alternative embodiment,components of the second network such as access points or cellular basestations may perform the mapping function by retrieving the necessaryinformation from the reader. Although this may prevent QoS in thetransmission channel between the RFID network and the second network,QoS may still be applied within the second network. Therefore, the lackof QoS is exchanged for a lower computation load on the reader.

In one embodiment, the information required to perform the mappingfunction may include the number of network traffic classes available.The number of available network traffic classes depends on the type ofnetwork that the reader is connecting to. Some examples are WLAN accesspoint with 802.11e support, QoS-enabled cellular base-station with 3GPP,and wired QoS with IP precedence/CoS (The latter wired network caseapplies to fixed location readers that are connected to a LAN and do notneed wireless access). In one example, the priority levels of the tagsare represented by 3 bits. Therefore, there are 8 possible tag prioritylevels that may be mapped into available network traffic classes. Inanother example, 2 tag priority bits are used to represent 4 tagpriority levels.

In one embodiment, there may be a one-to-one mapping between tagpriority levels and network traffic classes. The one-to-one mapping maymap the highest priority level on the RFID network to the highestpriority traffic class on the second network. This may continue untilthe lowest priority level on the RFID network is mapped to the lowestpriority traffic class. In one example embodiment, eight final prioritylevels from the RFID network are mapped to a second network using theIEEE 802.1D standard. The 802.1D standard is the IEEE Media AccessControl (MAC) bridges standard and is standardized by the IEEE 802.1working group. The 802.1D standard provides the following seven types oftraffic, where the numbers in parentheses are the traffic class valuescorresponding to each traffic type if there are eight queues availableat a given output port. The standard leaves as spare an eighth type,which could be used for traffic of more importance than background butless importance than best effort.

-   -   Network control (7): Both time-critical and safety-critical,        consisting of traffic needed to maintain and support the network        infrastructure, such as routing protocol frames.    -   Voice (6): Time-critical, characterized by less than 10 ms        delay, such as interactive voice.    -   Video (5): Time-critical, characterized by less than 100 ms        delay, such as interactive video.    -   Controlled load (4): Not time-critical but loss-sensitive, such        as streaming multimedia and business-critical traffic. A typical        use is for business applications subject to some form of        reservation or admission control, such as capacity reservation        per flow.    -   Excellent effort (3): Also not time-critical but loss-sensitive,        but of lower priority than controlled load. This is a        best-effort type of service that an information services        organization would deliver to its most important customers.    -   Best effort (2): Not time-critical or loss-sensitive. This is        LAN traffic handled in the traditional fashion.    -   Background (0): Not time-critical or loss-sensitive, and of        lower priority than best effort. This type includes bulk        transfers and other activities that are permitted on the network        but that should not impact the use of the network by other users        and applications.

In one embodiment, there may be a many-to-one mapping between prioritylevels in the RFID network and the second network. The difference in thenumber of priority levels available in the RFID network and secondnetwork may be due to the QoS standards used in the different networksor certain portions of the second network are non-operational or underrepair. This may lead to a situation where multiple tag priority levelsmap to a single network traffic class. Table 2 illustrates one exampleof mapping eight priority levels into a variety of available networktraffic classes. The table shows one example mapping when there are 8 orfewer traffic classes/queues available. In the first column, only onenetwork traffic class/queue is available so all priorities are mappedinto that class/queue. In the second column, there are twoclasses/queues available. Here, the higher 4 priority levels areassigned to the higher priority class/queue and the lower 4 prioritylevels are assigned to the lower priority class/queue. The remainingrows of the table can be explained similarly. This illustrates oneexample mapping however other mappings may also be applied.

TABLE 2 Example of mapping final calculated priorities into networkclasses/queues Number of Available Network Traffic Classes/Queues 1 2 34 5 6 7 8 Final 0 (default) 0 0 0 1 1 1 1 2 Calculated 1 0 0 0 0 0 0 0 0Priority 2 0 0 0 0 0 0 0 1 3 0 0 0 1 1 2 2 3 4 0 1 1 2 2 3 3 4 5 0 1 1 23 4 4 5 6 0 1 2 3 4 5 5 6 7 0 1 2 3 4 5 6 7

At 212, the reader may transmit the data received at 214 along with themapped network traffic class generated at 211 to the second network.Once received by the second network, the data may be distributed acrossthe network. The urgency in delivering the data will depend upon thepriority of the network traffic class. At 213, the reader may check forfurther events. If all events have been processed, then the reader hascompleted processing the command. If there are more events, the readermay interrogate the next RFID event. This occurs at 206. This sequentialprocessing of the RFID events may continue until all RFID eventsassociated with the received command are processed. The reader may thenreceive the next command in the queue, or if there are no commands, itmay enter an idle state until a new command is received.

FIG. 3 illustrates a RFID system according to one embodiment of thepresent invention. RFID system 300 comprises a RFID network and anothernetwork (i.e., a second network). RFID middleware and applicationsoftware for implementing RFID processes may have components distributedacross the reader, access point/base-station, router, and servercontroller for QoS support. Application software may be located on topof RFID middleware. In one example, both middleware firmware andapplication software may be updated by downloading newer versions fromthe network. RFID networks may include RFID readers coupled to RFID tagsthrough wireless technology, such as backscattering, for example. Inthis example embodiment, RFID system 300 includes a RFID networkcomprising RFID tags 301 through 306 and RFID readers 311 through 312.Reader 311 may interact with RFID tags 301 through 303 while reader 312may interact with RFID tags 304 through 306. RFID tags may also interactwith multiple RFID readers. In one example, RFID tag 303 may communicatewith RFID readers 311 and 312. This may occur in situations where a RFIDtag is within the range of more than one RFID reader. The RFID readersare coupled to the second network through various methods. These mayinclude wired local area network (“wired LAN”) access point, wirelesslocal area network (“wireless LAN”) access point, and cellular basestations.

In one embodiment, the RFID network communicates with the second networkthrough a wireless LAN access point (e.g., access points 321 or 322).Each wireless LAN access point may communicate with multiple readers.The access points may forward commands to the readers and retrieve datafrom the readers. In FIG. 3, internet/intranet enterprise application370 or server controller 360 may initiate a command to interrogate a setof tags. This command may be received by a router 350 and may betransmitted to wireless LAN access points 321 or 322. The access pointmay then forward the commands to the appropriate RFID readers. In oneexample, router 350, server controller 360, and internet/intranetenterprise applications 370 all support QoS. Therefore, the commands maybe received by the access points or readers in a different order thanthey were sent. The readers, equipped with wireless LAN radios, mayinterrogate the tags corresponding to the RFID events and read the datawithin the tag. In one example, each reader contains RFID middlewaresoftware that, amongst other things, may perform a filtering operationto filter duplicate and false tag reads. The readers forward the datathey read/filter to access points. The WLAN access points may providenetwork security, encryption, authentication, and bridge/route thewireless traffic to a wired Ethernet network or the Internet via arouter, for example.

The access points then forward the data to a router. In one embodiment,the router has additional middleware software components that mayperform some data processing functions before forwarding the data tointernet/intranet enterprise applications or server controllers wherethe RFID information is processed. In one example, the access pointshave some RFID middleware software components that, amongst otherthings, filters duplicate reads of the same tag by different readers. Inone example, access points may also act as routers so router 350 may beimplemented within wireless LAN access points 321 and 322. Since wiredLAN behaves similarly to wireless LAN, the embodiments and examplesdescribed above also apply to wired LAN.

In one embodiment, the RFID network communicates with the second networkthrough a cellular network. The cellular network may include cellularbase station 331 and 341 and cellular backbone systems 332 and 342.Cellular backbone systems may route data received from RFID readersthrough the cellular infrastructure (e.g., using QoS) and into a datanetwork to be received by router 350. It is to be understood that avariety of cellular networks with QoS may be used. As an example,cellular networks such as General Packet Radio Service (GPRS) orCellular Digit Packet Data (CDPD) may be used to provide services suchas packet switching. With packet switching, the routers determinedifferent paths for each packet and a packet assembler reconstructs thereceived out of order packets back into order. In one example, cellularbase stations and cellular backbone also support QoS. This may allow thecellular network to prioritize packets as they are received by thereaders. The data may travel through the cellular backbone where iteventually is forwarded to routers on the internet. Although FIG. 3illustrates cellular backbone 332 connected to the same router aswireless LAN access point 321, in practice it will be a differentphysical router. Since the cellular networks and wireless networks sharemany of the same traits, many of the functionalities illustrated abovefor wireless LAN may also be applied to cellular networks, and viceversa.

FIG. 4 illustrates a RFID system according to one embodiment of thepresent invention. RFID system 400 includes a RFID network and a secondnetwork. The second network comprises wireless LAN 420, router 430,server controller 440 and internet/enterprise applications 450. Thebehavior and performance of these components coupled in theconfiguration illustrated in FIG. 4 has been discussed in detail abovein FIG. 3. The RFID network comprises RFID tags 401 through 406 and RFIDreaders 411 through 413. In one embodiment, RFID readers 411 through 413are multimode radio readers. Multimode radio readers are readersequipped with multiple radios, thereby allowing them to communicate withmore than one network. This may allow multimode radio readers totransfer and receive data from other readers. In this exampleembodiment, RFID readers 411 through 413 may communicate with oneanother through network communication channel 460 using one networkprotocol while RFID readers 411 and 413 may communicate with wirelessLAN access point through network communication channel 470 using asecond network protocol. This may create additional capabilities formeeting QoS constraints by providing multiple networking options to thereader.

For example, the network used by the reader may depend on the finalpriority level. Reader 413 may need to transmit data received from RFIDtags 404 and 405 to distant wireless LAN access point 420. Since theenergy required for transmission is proportional to the square of thedistance between the source and the destination, significant energy maybe required from reader 413 to communicate directly with wireless LAN420. To minimize energy usage while meeting QoS requirements, reader 413may choose network paths according to the final priority level of thedata. If the final priority level of tag 404 is low, reader 413 maytransmit the data to nearby reader 412, which forwards the data to closeby reader 411, which forwards the data to access point 420. If the finalpriority level of tag 405 is high, reader 413 may transmit the datadirectly to access point 420 in order to avoid introducing extra delays,albeit with the cost of expending more energy. While FIG. 4 illustratestwo hops between readers 413 and access point 420, the number may rangeanywhere from one hop to several hops. Other advantages of multimoderadio readers may include monitoring network conditions on a secondnetwork. Network conditions such as signal strength, latency,throughput, or delay may be monitored on the second network. Bymonitoring the second network, the reader may switch from the currentnetwork to the second network when it is advantageous to do so. Thesesituations may arise due to a decreased load in the second network,decreased speed in the current network, change in the location of thereader, or problems in the current network such as weather or damagedcellular stations.

FIG. 5 illustrates a RFID system according to one embodiment of thepresent invention. System 500 includes a RFID network and a secondnetwork. The second network includes wireless LAN access point 520,cellular base station 531, cellular backbone 532, router 540, servercontroller 550, and internet/enterprise applications 560. The behaviorand performance of these components coupled in the configurationillustrated in FIG. 5 has been discussed in detail above in FIG. 3. TheRFID network comprises RFID tags 501 through 506 and RFID readers 511through 513. In one embodiment, RFID readers 511 through 513 aremultimode radio readers capable of transmitting data across variousnetworks depending on their position, battery power, network usage cost,and/or network conditions. These readers may be embedded in a portableelectronic device such as a PDA or a cell phone. In this example,readers 511 through 513 are capable of transmission by wireless LAN,cellular radios, and wireless ad-hoc/mesh. Reader 511 may connect towireless LAN access point 520 through network communication channel 580since it is positioned within the wireless network's range. Reader 512may connect to reader 513 through ad-hoc network communication channel570. An ad-hoc network is a self-configuring network comprising aplurality of mobile routers. The routers are free to move and organizethemselves, thereby creating a network topology that may change rapidlyand unpredictably. In this example, connecting reader 512 to the ad-hocnetwork 570 may save transmit energy when compared to a directtransmission to cellular base station 531 due to the shorter distancetraveled. This may result in savings in battery power. Reader 3 mayprimarily connect to cellular base station 531 through network 590because of network usage costs. These readers can also switch to anothernetwork if network conditions change. For example, if reader 511 in FIG.5 is mobile and moves to a location where the wireless LAN signal isweak, it can switch to cellular base station 531 provided the cellularsignal is stronger. This flexibility creates more robust networkscapable of withstanding changing network conditions and disasters.

The above description illustrates various embodiments of the presentinvention along with examples of how aspects of the present inventionmay be implemented. The above examples and embodiments should not bedeemed to be the only embodiments, and are presented to illustrate theflexibility and advantages of the present invention as defined by thefollowing claims. Based on the above disclosure and the followingclaims, other arrangements, embodiments, implementations and equivalentswill be evident to those skilled in the art and may be employed withoutdeparting from the spirit and scope of the invention as defined by theclaims. The terms and expressions that have been employed here are usedto describe the various embodiments and examples. These terms andexpressions are not to be construed as excluding equivalents of thefeatures shown and described, or portions thereof, it being recognizedthat various modifications are possible within the scope of the appendedclaims.

APPENDIX

1.0 QOS for 802.11e WLAN

802.11e is an IEEE specification to define QoS mechanisms for wirelessLAN equipment that gives support to bandwidth-sensitive applicationssuch as voice and video. The following overview of 802.11e is quotedfrom the original 802.11 media access control protocol was designed withtwo modes of communication for wireless stations. The first, DistributedCoordination Function (DCF), is based on Carrier Sense Multiple Accesswith Collision Avoidance (CSMA/CA), sometimes referred to as “listenbefore talk.” A station waits for a quiet period on the network andbegins to transmit data and detect collisions. DCF providescoordination, but it doesn't support any type of priority access of thewireless medium.

An optional second mode, Point Coordination Function (PCF), supportstime-sensitive traffic flows. Wireless access points periodically sendbeacon frames to communicate network identification and managementparameters specific to the wireless network. Between the sending ofbeacon frames, PCF splits the time into a contention-free period and acontention period. With PCF enabled, a station can transmit data duringcontention-free polling periods.

Because DCF and PCF do not differentiate between traffic types orsources, the IEEE developed enhancements in 802.11e to both coordinationmodes to facilitate QoS. These changes would let critical servicerequirements be fulfilled while maintaining backward-compatibility withcurrent 802.11 standards.

The enhancement to DCF—Enhanced Distribution Coordination Function(EDCF)—introduces the concept of traffic categories. Each station haseight traffic categories, or priority levels. Using EDCF, stations tryto send data after detecting the medium is idle and after waiting aperiod of time defined by the corresponding traffic category called theArbitration Interframe Space (AIFS). A higher-priority traffic categorywill have a shorter AIFS than a lower-priority traffic category. Thusstations with lower-priority traffic must wait longer than those withhigh-priority traffic before trying to access the medium.

To avoid collisions within a traffic category, the station counts downan additional random number of time slots, known as a contention window,before attempting to transmit data. If another station transmits beforethe countdown has ended, the station waits for the next idle period,after which it continues the countdown where it left off.

No guarantees of service are provided, but EDCF establishes aprobabilistic priority mechanism to allocate bandwidth based on trafficcategories.

Another way 802.11e aims to extend the polling mechanism of PCF is withthe Hybrid Coordination Function (HCF). A hybrid controller pollsstations during a contention-free period. The polling grants a station aspecific start time and a maximum transmit duration.

2.0: QoS for 3GPP Cellular

The 3rd Generation Partnership Program (3GPP) has augmented thecapabilities of General Packet Radio Service (GPRS) access to includeQoS support. QoS mechanisms provided in the cellular network have to berobust and capable of providing reasonable QoS. There are four different3GPP QoS classes; conversational, streaming, interactive, andbackground. These classes are designed to separate out traffic based ontheir sensitivity to delay. For example, the conversational class ismeant for traffic which is very delay sensitive while the backgroundclass is the most delay insensitive traffic class.

Conversational and streaming classes are mainly intended to be used forreal-time traffic flows. The conversational class is meant for the mosttime critical applications such as video telephony. Interactive andbackground classes are mainly meant to be used by traditional internetapplications like www, email, telnet, ftp, and news. These classesprovide looser delay but provide better error rate by means of channelcoding and retransmission. The interactive class has higher schedulingpriority than the background class and is mainly used by interactiveapplications (e-mail, web browsing), while the background class is meantfor background traffic (email download, ftp). Background applicationsuse transmission resources only when interactive applications do notneed them. This is very important in wireless environment where thebandwidth is scarce compared to fixed networks.

3.0: QoS for Wired LAN Routers

The following discussion applies to fixed location RFID readers with anEthernet connection to a router or high-end fixed location RFID readersthat also perform router functionalities. Once the RFID information ismapped into network classes then traffic shaping policy, trafficcontrol, and congestion control/avoidance can occur at the class level.Traffic shaping retains packets that are in excess of the maximumconfigured rate in a queue. Excess packets are then scheduled for latertransmission over a period of time. This transforms traffic bursts intoa smoothed packet output rate. An example of traffic control is to placebroadcast packets into a best effort or CoS level 0 class andsuppressing them when they exceed a preset percentage of total availablebandwidth. This prevents broadcast traffic from disrupting priorityqueues with guaranteed bandwidth. Congestion avoidance techniquesmonitor network traffic and provide preferential treatment for priorityclass traffic under congestion situations. For example, Weighted RandomEarly Detection (WRED) is a congestion avoidance method that dropspackets selectively based on IP precedence, where packets with a lowerIP precedence are more likely to be dropped than packets with a higherprecedence. For example, RFID packets that are in CoS/IP precedencelevel 5 (DSCP class Expedited Forwarding) would get preferentialtreatment over lower level packets.

After RFID data is mapped into a network traffic class the packets maybe marked. The router can use standard marking mechanisms such those forVoice over IP (VoIP). With the anticipated large volume of RFID data inthe future, RFID may also use a different marking mechanism thatdistinguishes RFID services and traffic classes from non-RFID traffic.

3.1: Packet Classification

In order to guarantee bandwidth for a class of packets a router, switch,or network node must be able to identify and group those packets fromother packets. The step that matches a packet to a class of traffic iscalled packet classification. Some methods used for classification arethe source and destination IP address in the IP header, port numbers inthe IP or UDP header, protocols such as URLs and IP precedence.

3.2: Packet Marking

After a packet is classified it is marked so that other nodes in thenetwork simply look at the marking to recognize the class of a packetand avoid repeating the processor intensive task of classification.Marking mechanisms that are similar include the six bits of the IPheader for Differentiated Services Code Point (DSCP) (Layer 3) thatenable differentiated service classes, the Type of Service (ToS) byte inthe IP header (Layer 3) where the three most significant bits usuallyreferred to as the IP precedence bits, and the three-bit 802.1p Class ofService (CoS) header field for prioritization (Layer 2) which works atthe media access control (MAC) layer and allows packets to be groupedinto various traffic classes. Other marking mechanisms include the ATMCell Loss Probability (CLP) bit for prioritizing packets in ATMnetworks, and the 3 EXP bits in the label header of Multiprotocol LabelSwitching (MPLS) for supporting differentiated services.

FIG. 6 shows how Differentiated Service (DS) class definitions aredefined in the IP header. The most significant 6 bits of the IP Type ofService (ToS) byte specify the DS class and are the DSCP bits. The mostsignificant 3 bits are also the IP precedence bits in IPv4. The last twobits are not used in IPv4 but are used for flow control for DiffServe.The first 3 bits of DSCP are class selector bits that represent thedifferent classes of service. IP precedence is compatible with DSCPbecause IP precedence also uses the 3 most significant bits to representclasses. This is illustrated in Table 3. IP precedence levels 0-5 alsocorresponds to CoS 0-5 respectively. Also shown in the table are IPPrecedence/CoS values 6 (Internet) and 7 (Network). High priority and/ordelay sensitive RFID packets should be marked with a CoS value of 5 forthe Layer 2 802.1p settings and a DSCP class value of “ExpediatedForwarding”, or IP Precedence value of 5. On the other hand, RFID datathat does not require priority treatment is more suitable for “AssuredForwarding” marking.

TABLE 3 Packet Priority Marking Layer 2 Class of IP Service IPPrecedence DSCP DSCP (CoS) Precedence Bits Bits Values DSCP Class 7 7111 111000 56-63 Network 6 6 110 110000 48-55 Internet 5 5 101 10100040-47 Expedited Forwarding 4 4 100 100000 32-39 Assured Forwarding 4 3 3011 011000 24-31 Assured Forwarding 3 2 2 010 010000 16-23 AssuredForwarding 2 1 1 001 001000  8-15 Assured Forwarding 1 0 0 000 0000000-7 Best Effort

The next two bits after the first 3 bits of DSCP are used to definepacket drop preferences (bits 3 and 4 in FIG. 6), and the last bit (bit5 in FIG. 6) must be 0 to indicate that DS classes have been set. Foreach of the 4 Assured Forwarding classes there are three possible droppreferences, resulting in 12 possibilities, as outlined in Table 4. Intimes of congestion the first packets to be dropped by Level 2 are thehigh drop preference packets.

TABLE 4 Assured forwarding classes with possible drop preference levelsAssured Assured Assured Assured Drop Forwarding Forwarding ForwardingForwarding Preferences 1 2 3 4 Low Drop 001010 010010 011010 100010Medium 001100 010100 011100 100100 Drop High Drop 001110 010110 0111101001103.3: QoS Queuing

Once packets are classified queuing techniques can be used by routers toprovide priority services and bandwidth guarantees. Packet loss andvariable delay is increased when different types of data with differentnetwork requirements are placed in the same queue. Network behavior ismore predictable when multiple queues are used. For example, highpriority or delay sensitive RFID packets need to be placed in a priorityqueue with guaranteed bandwidth and be separated from other datapackets. Queuing techniques include Low Latency Queuing, PriorityQueuing, First In First Out (FIFO) queuing, Class-Based Weighted FairQueuing, Enhanced Distributed Coordination Function, and Custom Queuing.For example, the LLQ queuing method provides a priority queue forcertain traffic classes and guaranteed minimum bandwidth for otherclasses. It also has a default class for all traffic that isunclassified. LLQ allows the specification of queue depths to determinewhen a router should drop waiting packets on any class queue.

1. A system for providing quality of service, the system comprising: anRFID first network; and a second network communicatively coupled to theRFID first network; the RFID first network comprising: a set of tags;and a set of readers, each reader configured to: receive data from oneor more tags; retrieve RFID priority information corresponding to saidRFID first network; determine an RFID priority level corresponding tothe RFID first network for the data received from each tag based on theretrieved RFID priority information; map the RFID priority level for thedata received from each tag into an associated priority levelcorresponding to the second network, wherein the RFID priority level forone or more tags is different than the tags associated priority levelscorresponding to the second network; and send, to the second network, anRFID response for each tag comprising the data received from the tag andthe associated priority level corresponding to the second network. 2.The system of claim 1, wherein retrieving the RFID priority informationcomprises retrieving the RFID priority information stored on one or moretags.
 3. The system of claim 2, wherein each reader is furtherconfigured to modify the RFID priority information stored on a tag. 4.The system of claim 3, wherein each reader is further configured totransmit the modified RFID priority information on the tag to one ormore other readers of the RFID first network.
 5. The system of claim 1,wherein retrieving the RFID priority information comprises retrievingthe RFID priority information stored on a reader.
 6. The system of claim5, wherein each reader is further configured to update RFID priorityinformation stored on the reader with the retrieved RFID priorityinformation when the retrieved RFID priority information is differentfrom the RFID priority information stored on the reader.
 7. The systemof claim 1, wherein the RFID priority information comprises a prioritylevel of a tag and a priority level of a reader, wherein retrieving theRFID priority information comprises retrieving the priority level of thetag and the priority level of the reader.
 8. The system of claim 7,wherein determining the RFID priority level comprises performing acalculation based on the priority level of the tag and the prioritylevel of the reader.
 9. The system of claim 7, wherein the RFID prioritylevel is a higher of the priority level of the tag and the prioritylevel of the reader.
 10. The system of claim 7, wherein the RFIDpriority level is an average of the priority level of the tag and thepriority level of the reader.
 11. The system of claim 1, whereinretrieving the RFID priority information comprises retrieving the RFIDpriority information stored on the second network.
 12. The system ofclaim 11, wherein the RFID priority information stored on the secondnetwork is cached on an access point in the second network.
 13. Thesystem of claim 1, wherein the RFID priority information is stored onone or more readers.
 14. The system of claim 1, wherein the RFIDpriority information is based on attributes of the RFID first network.15. The system of claim 14, wherein the attributes of the RFID firstnetwork include a location of a reader, a time, or an application typethat is supported by the reader.
 16. The system of claim 1, wherein thesecond network is a wired local area network, a wireless local areanetwork, or a cellular network.
 17. The system of claim 1, whereinmapping the RFID priority level to the associated priority levelcorresponding to the second network comprises converting the RFIDpriority level to a priority level of the second network by applying amapping algorithm to the RFID priority level.
 18. The system of claim 1,wherein the RFID priority level is mapped to the associated prioritylevel corresponding to the second network based on the RFID prioritylevel determined for the data received, a number of RFID priority levelsavailable on the RFID first network, and a number of available prioritylevels on the second network.
 19. The system of claim 1, wherein thesecond network comprises a set of access points and routers, wherein theaccess points and routers are configured to process a plurality of RFIDresponses in an order based on second network priority levels associatedwith the plurality of RFID responses.
 20. The system of claim 1, whereinthe RFID priority level for the data received from each tag is set togive a higher prioritization to time consuming operations within theRFID first network or the second network in order to speed up sendingtime-sensitive data to their destinations.
 21. A method of providingquality of service in an RFID first network comprising a set of tags anda set of readers, the RFID first network communicatively coupled to asecond network, the method comprising: at a reader, receiving a requestfrom the second network for reading data from a plurality of tags in theset of tags; retrieving priority information corresponding to each tagin the plurality of tags; determining a priority level corresponding toeach tag in the plurality of tags based on the retrieved priorityinformation; and at the reader, reading data from each tag in theplurality of tags by interrogating each tag in the plurality of tagsbased on the determined priority levels.
 22. The method of claim 21further comprising: associating a priority level to the data read fromeach particular tag by mapping the determined priority levelcorresponding to each tag to a priority level associated with the secondnetwork; and sending the data read from each tag to the second networkbased on the corresponding priority level associated with the secondnetwork.
 23. The method of claim 21, wherein retrieving the priorityinformation corresponding to each tag in the plurality of tags comprisesretrieving priority information stored on the RFID first network. 24.The method of claim 23, wherein the priority information that is storedon the RFID first network is stored on the reader.
 25. The method ofclaim 21, wherein the priority information corresponding to each tag inthe plurality of tags is not stored in the RFID first network, whereindetermining the priority level corresponding to each tag comprises usingpriority information received from the second network.
 26. The method ofclaim 21 further comprising: associating a priority level to the dataread from each particular tag by combining the determined priority levelcorresponding to the particular tag and a priority level for the reader;mapping the combined priority level for data read from each tag to apriority level associated with the second network; and sending the dataread from each tag to the second network based on the correspondingpriority level associated with the second network.
 27. The method ofclaim 21, wherein the priority level corresponding to each tag is set togive a higher prioritization to time consuming operations within theRFID first network or the second network in order to speed up sendingtime-sensitive data to their destinations.
 28. The method of claim 21,wherein the data read from one or more tags comprises a priority levelstored in the tag, the method further comprising: when the prioritylevel received from a particular tag is different from the determinedpriority level corresponding to the particular tag, storing the prioritylevel received from the particular tag in the RFID first network as thepriority level corresponding to the particular tag.
 29. The method ofclaim 21, wherein the second network comprises a set of wireless accesspoints, wherein at least one access point filters duplicate data readfrom a same tag by different readers.
 30. A system for providing qualityof service, the system comprising: an RFID first network; a secondnetwork communicatively coupled to the RFID first network; the RFIDfirst network comprising: a set of tags; and a set of readers, eachreader configured to: receive a request from the second network forreading data from a plurality of tags in the set of tags; retrievepriority information corresponding to each tag in the plurality of tags;determine a priority level corresponding to each tag in the plurality oftags based on the retrieved priority information; and read data fromeach tag in the plurality of tags by interrogating each tag in theplurality of tags based on the determined priority levels.
 31. Thesystem of claim 30, wherein each reader is further configured to:associate a priority level to the data read from each particular tag bymapping the determined priority level corresponding to each tag to apriority level associated with the second network; and send the dataread from each tag to the second network based on the correspondingpriority level associated with the second network.
 32. The system ofclaim 30, wherein each reader is further configured to: associate apriority level to the data read from each particular tag by combiningthe determined priority level for the particular tag and a prioritylevel for the reader; map the combined priority level for data read fromeach tag to a priority level associated with the second network; andsend the data read from each tag to the second network based on thecorresponding priority level associated with the second network.
 33. Thesystem of claim 30, wherein the priority level corresponding to each tagis set to give a higher prioritization to time consuming operationswithin the RFID first network or the second network in order to speed upsending time-sensitive data to their destinations.
 34. The system ofclaim 30, wherein retrieving the priority information corresponding toeach tag in the plurality of tags comprises retrieving priorityinformation stored on the RFID first network.
 35. The system of claim34, wherein the priority information that is stored on the RFID firstnetwork is stored on the reader.
 36. The system of claim 30, wherein thepriority information corresponding to each tag in the plurality of tagsis not stored in the RFID first network, wherein determining thepriority level corresponding to each tag comprises using priorityinformation received from the second network.
 37. The system of claim30, wherein the data read from one or more tags comprises a prioritylevel stored in the tag, wherein each reader is further configured tostore, when the priority level received from a particular tag isdifferent from the determined priority level corresponding to theparticular tag, the priority level received from the particular tag inthe RFID first network as the priority level corresponding to theparticular tag.
 38. The system of claim 30, wherein the second networkcomprises a set of wireless access points, wherein at least one accesspoint filters duplicate data read from a same tag by different readers.